In different applications, it may be useful to drain liquids from an enclosure with minimal corresponding loss of gases. For example, in many installations, enclosures can contain electrical equipment that generates heat. Accordingly, to maintain a desired temperature range (e.g., to prevent damage to thermally sensitive components), the interiors of the enclosures may need to be cooled. In some cases, air conditioners can be installed to provide appropriate cooling. However, the operating of air conditioners can cause moisture in the air inside the enclosure to condense. Accordingly, use of air conditioners (or various other factors), can result in liquids (e.g., liquid water condensate) that need to be removed from an enclosure.
In many conventional systems, drains for removing liquid from an enclosure (e.g., conventional condensate drains) can also allow gas to move out of (or into) the enclosure. In some installations, this may be undesirable. For example, some configurations of purge and pressurization systems (e.g., for use in hazardous locations) can prevent environmental gases from entering an enclosure by pressurizing the internal area of an enclosure. In these systems, the pressures provided (e.g., 0 to 1000 Pa) can sometimes result in significantly costly losses of pressurized air, particularly if flow rates become sufficiently large to overcome associated leakage compensation systems.
In some configurations, conventional drains can be provided with traps, which can help to reduce loss of air (e.g., due to internal pressurization of an enclosure). However, conventional drains can suffer from various deficiencies. For example, conventional drains with traps can require priming to seal, via a small amount of water being dispensed (and maintained) within the trap. Over time, this water can evaporate or otherwise be lost, thereby allowing the traps to dry out and air to escape.